CX500 GL500 650 Global

Is there any way to tell the difference between the US/Canada speedometer ratio's for the 78, 79, and 80.
The 78 speedo is 0-120mph
79 speedo 0-120mph
80 speedo 0-85mph.

I just got done counting the gears on the speedo gear on the wheel and both the 78 and 79 have 26 teeth on them and then they go into a worm gear.

I was told that most honda speedos are the same but now I am thinking its wrong. Something about the speedo gear doing all the work and keeping the speedometers all the same.

Anybody have any info on this?

When I was building my sons 80 Custom, I had to figure out which one of the 2 speedometer drive gears that I had went to it. I had one from my old 78 parts, and had placed them both together. I took them apart and the gears had the same number of teeth. The only difference was a small slot tab molded to the one for the 80 that fit a tab on the fork body so it would be mounted the same every time. The 78 does not have this tab.

Sense the gears are the same count, it would reason that the speedometers are geared the same way too. Just the angle of the cable mount is different from the 78 standards or deluxe, compared with the Custom models. As well as the housing that they are mounted in as we already know.

The needle is not driven by a gear though. It moves by spinning a magnet inside a metal bell that floats above it. As the magnet spins faster, the bell tries to keep up with it due to the spinning magnetic field.

Problem solved they all seem to be the same but with years of wear and tear and idle use the three I have seem to be responding different on the low end. I readjusted them and they are all withing a few miles on the low end and the high end now.
Just for future reference does anyone know the speedometer ratio that these run on in case someone buy an aftermarket.
Is it 2240:60 ratio.